The invention concerns a jack with a single leg, with a lifting arm that pivots around a stationary horizontal axis on the leg, with a threaded shaft that is articulated to the leg and engages the lifting arm either directly or by way of lever arms articulated to the leg, and with a manually operated crank that has non-rotationally secured to its end a claw that has a transverse slot and sides that can be employed to attach the claw to a transverse bolt on the end of the shaft loosely enough to allow the crank to activate the shaft even when it is not aligned with it.
Providing a jack, especially a scissoring jack or a two-point articulation jack of the scissoring type, with a detachable crank to overcome the unavoidable distance between the jack and its user is generally known. Using a slip-over polygon to attach such a crank is also generally known. Alternatively, providing the shaft of such a jack with an eye and the crank with a hook that hooks into the eye and entrains the shaft when the crank is rotated is known.
A jack with the aforesaid characteristics is known from German GM 8 701 736. The claw has an open slot that is longitudinal and hence parallel to the shaft of the crank. The slot fits over one end of a transverse bolt. The other side of the claw has another slot that slides over the bolt. The slots in the two sides fit loosely enough over the bolt to allow use of the crank even when its shaft is not aligned with the threaded shaft. The crank will accordingly not separate unintendedly from the jack. It has, however, been discovered that this mode of attachment is not evident or at least not obvious to an uninstructed user.